There is a growing demand in the US for more trained engineers, yet attrition rates from university engineering programs are high and diversity in engineering is low. Few resources have been dedicated to the improvement of freshman engineering courses even though freshman students have the highest rates of attrition. Through a synthesis of the literature on inclusive tools and participant structures in educational settings, we developed, implemented, and researched a freshman mechanical engineering design course that incorporated elements of project-based learning, collaboration, service-learning, and customer-oriented design through a partnership with a local elementary school. Our research was grounded in the value and competence belief constructs defined by expectancy-value theory. Engineering values include enjoying engineering tasks, viewing engineering as useful, and identifying as an engineer and engineering competence beliefs encompass beliefs in one's engineering abilities in the present, as well expectancies for success in the future. Rich qualitative data collected from undergraduate participants suggested that this course was highly valued and helpful for increasing engineering-related competence beliefs. Further, these positive impacts were consistent across gender. From our results, we provide recommendations for strategies to help grow and diversify engineering.